1 files changed, 114 insertions, 0 deletions
diff --git a/src/pico/adafruit_register/i2c_bcd_datetime.py b/src/pico/adafruit_register/i2c_bcd_datetime.py
new file mode 100755
index 0000000..2bb458a
--- /dev/null
+++ b/src/pico/adafruit_register/i2c_bcd_datetime.py
@@ -0,0 +1,114 @@
+# SPDX-FileCopyrightText: 2016 Scott Shawcroft for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+# pylint: disable=too-few-public-methods
+
+"""
+`adafruit_register.i2c_bcd_datetime`
+====================================================
+
+Binary Coded Decimal date and time register
+
+* Author(s): Scott Shawcroft
+"""
+
+__version__ = "0.0.0+auto.0"
+__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Register.git"
+
+import time
+
+try:
+    from typing import Optional, Type
+    from typing_extensions import Literal
+    from circuitpython_typing.device_drivers import I2CDeviceDriver
+except ImportError:
+    pass
+
+
+def _bcd2bin(value: int) -> int:
+    """Convert binary coded decimal to Binary
+
+    :param value: the BCD value to convert to binary (required, no default)
+    """
+    return value - 6 * (value >> 4)
+
+
+def _bin2bcd(value: int) -> int:
+    """Convert a binary value to binary coded decimal.
+
+    :param value: the binary value to convert to BCD. (required, no default)
+    """
+    return value + 6 * (value // 10)
+
+
+class BCDDateTimeRegister:
+    """
+    Date and time register using binary coded decimal structure.
+
+    The byte order of the register must* be: second, minute, hour, weekday, day (1-31), month, year
+    (in years after 2000).
+
+    * Setting weekday_first=False will flip the weekday/day order so that day comes first.
+
+    Values are `time.struct_time`
+
+    :param int register_address: The register address to start the read
+    :param bool weekday_first: True if weekday is in a lower register than the day of the month
+        (1-31)
+    :param int weekday_start: 0 or 1 depending on the RTC's representation of the first day of the
+        week
+    """
+
+    def __init__(
+        self,
+        register_address: int,
+        weekday_first: bool = True,
+        weekday_start: Literal[0, 1] = 1,
+    ) -> None:
+        self.buffer = bytearray(8)
+        self.buffer[0] = register_address
+        if weekday_first:
+            self.weekday_offset = 0
+        else:
+            self.weekday_offset = 1
+        self.weekday_start = weekday_start
+        # Masking value list   n/a  sec min hr day wkday mon year
+        self.mask_datetime = b"\xFF\x7F\x7F\x3F\x3F\x07\x1F\xFF"
+
+    def __get__(
+        self,
+        obj: Optional[I2CDeviceDriver],
+        objtype: Optional[Type[I2CDeviceDriver]] = None,
+    ) -> time.struct_time:
+        # Read and return the date and time.
+        with obj.i2c_device as i2c:
+            i2c.write_then_readinto(self.buffer, self.buffer, out_end=1, in_start=1)
+        return time.struct_time(
+            (
+                _bcd2bin(self.buffer[7] & self.mask_datetime[7]) + 2000,
+                _bcd2bin(self.buffer[6] & self.mask_datetime[6]),
+                _bcd2bin(self.buffer[5 - self.weekday_offset] & self.mask_datetime[4]),
+                _bcd2bin(self.buffer[3] & self.mask_datetime[3]),
+                _bcd2bin(self.buffer[2] & self.mask_datetime[2]),
+                _bcd2bin(self.buffer[1] & self.mask_datetime[1]),
+                _bcd2bin(
+                    (self.buffer[4 + self.weekday_offset] & self.mask_datetime[5])
+                    - self.weekday_start
+                ),
+                -1,
+                -1,
+            )
+        )
+
+    def __set__(self, obj: I2CDeviceDriver, value: time.struct_time) -> None:
+        self.buffer[1] = _bin2bcd(value.tm_sec) & 0x7F  # format conversions
+        self.buffer[2] = _bin2bcd(value.tm_min)
+        self.buffer[3] = _bin2bcd(value.tm_hour)
+        self.buffer[4 + self.weekday_offset] = _bin2bcd(
+            value.tm_wday + self.weekday_start
+        )
+        self.buffer[5 - self.weekday_offset] = _bin2bcd(value.tm_mday)
+        self.buffer[6] = _bin2bcd(value.tm_mon)
+        self.buffer[7] = _bin2bcd(value.tm_year - 2000)
+        with obj.i2c_device:
+            obj.i2c_device.write(self.buffer)